How are you hearing no difference?


In my experience, I've never heard two pre-amps that sound exactly the same, nor two DACs that sound the same, nor two amps...etc. Yet, occasionally someone will claim that they heard no difference between Product A and Product B in their system.  I find it difficult to believe.
128x1284hannons

Some very good points made here. I take care quite often to have a friend come help blind test; I also compare over time, and get my wife's "golden ears" opinion until she gets annoyed (humor).

I understand and agree that certain components will sound similar, especially DAC's. I've had to do some very careful listening to reveal the smallest of differences. On one occasion, the difference was so slight, it came down to a two second section where I could hear a difference of a faint bongo beat that DAC A presented with more percussion than DAC B (about the 6:56-58 mark on the song "Morning Mist" performed by Ahmad Jamal).

If you think that two components sound the same, then you need to keep listening until you hear the difference.

I'll admit that sometimes the differences can be so small they aren't worth mentioning or not meaningful enough. In the DAC comparison I described above, that difference had meaning to me, small as it was.

cleeds, I do not think it would be that difficult at all to design a randomized, double blinded study for audiophiles. I'm not saying it wouldn't be a little complex but it wouldn't be hard.

The issue is who would need such a test and why. I do not think it is useful for an individual audiophile for whom the only determinant is "what do I like better".

However, for critics (whose descriptions of equipment SQ all seem to sound the same) or for magazines/web sites that compare equipment I think such tests would be very valuable and legitimizing if results corroborate critical assessments. I deeply suspect that they wouldn't.....and that's why it isn't done.

Many areas in medicine that were once dominated by the diagnostic proficiency of experience physicians have gone by the wayside because studies show that many aspects of the physical exam are not nearly as sensitive or specific as physicians claimed and swore that they were.

4hannons, if I think two pieces of equipment sound the same then I'm done. Why spend time trying to hear a difference that is so minute as to be irrelevant? As you say, the key word is "relevant" I suppose.
n80
I do not think it would be that difficult at all to design a randomized, double blinded study for audiophiles. I'm not saying it wouldn't be a little complex but it wouldn't be hard.
It's fairly easy to design such a test, but it is a real challenge to actually conduct such a test if you want it to be scientifically valid. It's a tedious and laborious undertaking on the parts of all, including the test subjects. 
The issue is who would need such a test and why. I do not think it is useful for an individual audiophile for whom the only determinant is "what do I like better". 
Agreed!

n80 - I don't find it useful when someone describes two components sounding the same, that's my point. It just makes sense to me to find the difference if you've taken an interest to compare. Notice I'm not saying "better", a subjective term but sometimes useful.  I suppose someone can argue that the term "different" is subjective as to the skill of the listener, the equipment, if detectable, etc.